The civic-run Brihanmumbai Electric Supply and Transport (BEST) undertaking on Monday served a "blacklisting" notice to private firm Causis E-Mobility for its alleged failure to supply 700 electric double-decker buses as per a contract awarded to it, a senior official said.

BEST general manager Vjay Singhal told reporters the premier public transport undertaking had awarded tender for supply of 900 double-decker electric buses to two firms, of which Causis E-Mobility was to provide 700.